Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Foreign currency translation, Taxes	$ (7)	$ (14)	$ 6	$ (24)
Change in net unrealized losses on available-for-sale securities, Taxes	28	(11)	336	347
Change in net unrealized losses on available-for-sale securities designated in fair value hedges, Taxes	4	9	9	(6)
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, Taxes	1	1	2	3
Change in net unrealized losses on cash flow hedges, Taxes	(15)	(27)	(179)	(144)
Change in unrealized losses on retirement plans, Taxes	$ 0	$ (1)	$ 2	$ 2